At a time when the United States and other countries are on a constant terrorism alert, the authentication of identity documents has taken on an unprecedented level of importance. In addition to screening those crossing U.S. Borders, identity documents are required for access to “secure areas” at airports and seaports. With the advent of modern color copiers and lamination equipment it has become relatively easy to create counterfeits of identity documents.
Typically holograms or color shifting inks have been used as methods of providing authentication to such documents. Other overt and/or covert technologies have been used to attempt to create secure documents.